Research On An Optical Line Scanning And Super Resolution Interferometry System For On-line Measurement Of Precision Surface

With the development in the fields of advanced manufacture, aerospace, optics,biomedicine,material,micro-electronics, micro-electro-mechanical system etc, there emergies a lot of precision and super-precision surfaces. These precision and super precision surfaces influence greatly the usage characteristics of the corresponding products. It is very important to measure these surfaces precisely for design,manufacture and using of the products. The development of many fields requires non-contact measurement, high precision measurement, high speed measurement and on-line measurement for these precision and super precision surfaces. The available surface measurement methods can not satisfy these requirements. An optical line scanning and super resolution interferometry system for on-line measurement of precision surface has been presented, which can conduct non-contact, high precision,high speed and on-line measurement for precision and super precision surfaces.The measrement system includes three parts which are optical-line scanning precision surface interferometric measurement system, feedback stabilization system and super lateral resolution measurement system. Firstly, an optical-line scanning precision surface interferometric measurement system has been researched. The light from a broadband light source is dispersed to be a parallel plate with wavelengths distributing continuously in the lateral direction. The optical plate has been focused to be an optical line to scan the measured surface for performing non-contact, high precision and high speed measurement. Secondly, in order to make the interferometric measurement system for on-line measurement,a feedback stabilization system has been developed for compensating the environmental disturbances to the measurement system and thus endowing the measurement system with high ability for resisting environmental disturbances. And therefore,the measurement system is suitable for on-line measurement. Thirdly, an one-dimensional optical amplitude filter is developed for improving the lateral resolution. The optical diffraction limit has been broken by using the one-dimensional optcail amplitude filter and super lateral resolution has been achieved. Finally, an optical-line scanning super-resolution precision surface interferometric on-line measurement system has been developed which can realized non-contact, high precision, high speed, super-resolution and on-line measurement for precision surface.The main innovations are listed below.1. An optical-line scanning precision 3-D surface interferometric measurement system has been developed. Only one dimensional scanning action is needed for realizing 3-D surface measurement. Compared to the optical spot scanning measurement mode,the optical line scanning measurement mode has not only improved the measurement speed but also simplified the configuration of the measurement system greatly. The cost of the measurement system has also been depressed. The simplified configuration of the system has decreased the number of error sources and has provided the possibility of high precision measurement.2. The wavelengths that incident onto different measured points on the measured surface are different and fixed, and the measurement results will be traced to wavelength accurately. not influenced by the drifting of the spectrum of the light source.A blazed grating has been introduced for dispersing the light from a broadband light source to form a parallel plate with the wavelengths distributing continuously in the lateral direction. Only the positions of the optical elements in the system have been fixed, the wavelength incidented onto each measured point on the surface will be fixed, not influenced by the drifting of the spectrum of the light source. So the measurement results will be traced to wavelength accurately.3. A feedback stabilization system is developed for compensating the environmental disturbances. The interferometer has been stabilized and the measurement system is suitable for on-line measurement4. An one-dimensional optical amplitude filter has been designed. The width of the focused line has been compacted. The optical diffraction limit has been broken in the optical line width direction and super-resolution has been achieved.